JPH11305101A - Lens barrel for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel for a camera constituted so that a coupling means and a moving frame can be easily coupled. SOLUTION: This lens barrel is provided with the coupling means 123 and 143 respectively coupling the first and the second moving frames 121 and 141 and respective driving means moving the frames 121 and 141 and having fitting parts 123b and 143b fitted with the frames 121 and 141 by elastic force, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a camera such as a video camera.

[0002]

2. Description of the Related Art A lens barrel for an inner focus type camera having a zoom lens system including four groups of lenses and an image sensor such as a CCD has been known. The camera lens barrel includes a front lens barrel, a Z-moving frame, an intermediate lens barrel, an F-moving frame, and a rear lens-barrel. , The intermediate barrel, the F-movement frame, and the rear barrel.

The front lens barrel, the intermediate lens barrel, and the rear lens barrel are connected and fixed in this order. And the Z movement frame is
The F-movement frame is disposed inside the intermediate barrel and between the front barrel and the intermediate barrel so as to be movable between the front barrel and the intermediate barrel. It is arranged to be movable. That is, the Z moving frame is locked by the Z guide shaft bridged between the front barrel and the intermediate barrel, and is controlled to move along the Z guide shaft by driving the stepping motor.
The F-movement frame is also locked by an F-guide shaft spanned between the rear barrel and the intermediate barrel, and is controlled to move along the F-guide shaft by driving a stepping motor.

In order to assemble the camera lens barrel having such a configuration, first, one end of the Z guide shaft is pressed into a Z-axis mounting portion of the Z guide shaft provided on the intermediate barrel,
One end of the guide shaft is pressed into the F-axis mounting portion of the F guide shaft provided in the intermediate lens barrel. Next, a Z moving frame 3 as shown in FIG. 7 is inserted and engaged from the other end of the Z guide shaft, and a connecting portion 2 that can move linearly in synchronization with the rotation of the stepping motor 1 provided in the stepping motor 1. Into the connecting portion 4 provided on the Z moving frame 3. Then, the other end of the Z guide shaft is press-fitted into a Z-axis mounting portion of the Z guide shaft provided in the front barrel, and the front barrel and the intermediate barrel are screwed.

Further, an F moving frame 7 as shown in FIG.
The connecting portion 6 that is inserted and engaged from the other end of the guide shaft and that can move linearly in synchronization with the rotation of the stepping motor 5 provided on the stepping motor 5 is fitted to the connecting portion 8 provided on the F moving frame 7. Put in. Then, the other end of the F guide shaft is press-fitted into an F-axis mounting portion of the F guide shaft provided in the rear barrel, and the rear barrel and the intermediate barrel are screwed. Finally, the stepping motors 1 and 5 are screwed to the intermediate lens barrel, and the iris and the like are screwed to the intermediate lens barrel.

[0006]

The above-described conventional camera lens barrel has a relatively large outer shape, and has a space between each of the stepping motors 1, 5 and the Z moving frame 3 and the F moving frame 7. Since there was room, relatively large connecting portions 2 and 6 could be incorporated, but with the recent miniaturization of camera lens barrels, it became difficult to incorporate such connecting portions 2 and 6. It has become. Therefore, a small connecting nut for connecting each stepping motor to the Z-moving frame and the F-moving frame is separately arranged to cope with the downsizing of the camera lens barrel.

However, if play occurs at the connecting portion between the connecting nut and the Z-moving frame and the F-moving frame, there is a problem that hysteresis occurs when the Z-moving frame and the F-moving frame are reversed, and they cannot follow. On the other hand, when the connecting portion between the connecting nut and the Z moving frame and the F moving frame is tight, the vibration of each stepping motor is transmitted to the second lens unit and the fourth lens unit as they are, causing a problem that image shaking occurs. Therefore, the fitting accuracy of the connecting portion between the connecting nut and the Z-moving frame and the F-moving frame has to be processed with high accuracy, for example, ± 0.003 mm, which leads to an increase in processing cost.

The present invention has been made in view of the above circumstances, and has as its object to provide a camera lens barrel that can easily connect a connecting means to a moving frame.

[0009]

According to the present invention, there is provided a front lens barrel having a first group lens, a first moving frame having a second group lens, and an intermediate mirror having a third group lens. Tube,
In a camera lens barrel including a second movable frame having a fourth group lens and a rear barrel having an image sensor, the first and second movable frames and the first and second movable frames are respectively moved. This is achieved by providing a connecting means for connecting the respective driving means with each other, the connecting means having a fitting portion fitted to each of the first and second moving frames by an elastic force.

According to the above construction, the fitting portion provided in the connecting means is elastically deformed and fitted to each moving frame, so that the fitting accuracy of the connecting portion between the connecting means and each moving frame movement is improved. Hysteresis does not occur at the time of reversing the movement of each moving frame even if processing is not performed with high precision, and it is possible to follow smoothly, and vibration of each motor is directly transmitted to the second lens group and the fourth lens group. However, the occurrence of image shaking can be prevented.

[0011]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description in the following description. It is not limited to these forms unless otherwise stated.

FIG. 1 is an exploded perspective view showing an embodiment of a camera lens barrel according to the present invention, and FIG. 2 is a sectional side view thereof. The camera lens barrel 100 is an inner focus type camera lens barrel having a zoom lens system composed of four groups of lenses. The lens barrel 100 has positive, negative, positive, and positive in order from the subject side along the optical axis I. First lens unit 11 with refractive power
0, a second group lens 120, a third group lens 130, and a fourth group lens 140 are provided, and an image pickup device such as a CCD (not shown) is arranged at a focal position of the fourth group lens 140.

The first group lens 110 is a focusing lens group which is fixed in a lens barrel and focuses an image of a subject. In the illustrated case, the first lens group 110 includes three lenses. Second lens group 1
Reference numeral 20 denotes a zoom (magnification) lens unit that moves to the image plane side along the optical axis I in the lens barrel and performs magnification from the wide end to the telephoto end. In the illustrated case, three lenses are used. It is composed of The third lens group 130 is a correction lens group that is fixed in the lens barrel and corrects an image plane variation due to zooming. In the illustrated case, the third lens group 130 is composed of one lens. Fourth lens group 1
Reference numeral 40 denotes a focusing lens group that moves along the optical axis I in the lens barrel to perform focusing (focusing). In the illustrated example, the focusing lens group 40 includes two lenses.

The camera lens barrel 100 includes a front barrel 111, a Z movable frame 121, an intermediate barrel 131, an F movable frame 141, and a rear barrel 151. Front lens barrel 11
1, a first lens unit 110 is fixedly supported by caulking or the like.
2 is fixed to one end surface of the intermediate lens barrel 131. The rear lens barrel 151 is provided with an element mounting portion 152 for mounting an image sensor, and is fixed to the other end surface of the intermediate lens barrel 131 by a tapping screw 153.

The Z-movement frame 121 has a second group lens 120
Is fixedly supported by caulking or the like.
Reference numeral 21 is movably housed inside the one end surface of the intermediate lens barrel 131. In the F movement frame 141, the fourth lens group 1
The F-movement frame 141 is movably housed inside the other end surface of the intermediate lens barrel 131.

That is, the Z moving frame 121 is provided with the front lens barrel 111.
And two Z guide shafts 124 extending in parallel between the Z-axis mounting portions 113 and 133 shown in FIG. 3 provided on the intermediate lens barrel 131, respectively, and connected by the driving of the stepping motor 122. It is configured to be able to control movement along a Z guide shaft 124 via a nut 123. The F-movement frame 141 also includes the rear barrel 151 and the intermediate barrel 13.
F-axis mounting portions 15 shown in FIG.
The stepping motor 142 is driven by the stepping motor 142 so as to be movable along the F guide shaft 144 via the connection nut 143. I have.

In the intermediate lens barrel 131, a third lens group 130 is fixedly supported at a substantially central portion by caulking or the like, and stepping motors 122 and 142 for moving the Z-moving frame 121 and the F-moving frame 141 are provided on the side surface. Motor mounting portions 132a, 132b for mounting;
An iris attachment portion 132c for attaching the iris 0 is provided. The stepping motors 122 and 142 are inserted into the motor mounting portions 132a and 132b and fixed by tapping screws 125 and 145. Iris 160
Are inserted from the iris mounting portion 132c so as to intersect with the optical axis I and are fixed by tapping screws 161.

FIG. 4 shows the Z moving frame 121 and the connecting nut 12.
FIG. 3 is an exploded perspective view showing the details of No. 3; The Z movement frame 121 is
At one end of the lens frame 121a into which the second group lens 120 is fitted, a sleeve portion 121b extending in the direction of the optical axis I is integrally provided, and approximately 180 ° from the sleeve portion 121b.
A U-shaped groove 121c is provided at one end of the separated lens frame 121a. The Z moving frame 12 is provided on the sleeve portion 121b.
A groove 121d into which a connecting nut 123 for connecting the first motor 1 and the stepping motor 122 is inserted is formed. A portion 121e is formed, and a concave nut fitting portion 121f into which the connecting nut 123 is fitted is formed at the center of the groove 121d.

The connecting nut 123 is housed in the groove 121d and has a pipe portion 123 into which the Z guide shaft 124 is inserted.
a and a nut fitting portion 12 formed integrally with the side surface thereof.
It includes a convex fitting portion 123b fitted to 1f, a rack portion 123c that meshes with and supports the lead screw 122a of the stepping motor 122, a stopper portion 123d, and a clamp spring portion 123e. As shown in FIG. 5, the fitting portion 123b, which is a characteristic portion of the present invention, is integrally formed with the connection nut 123, and
A slit 123ba is provided at the center so that it can be fitted to 1f by elastic force. In the above configuration, the F moving frame 141 and the connection nut 143 are the same.

The camera lens barrel 10 having the above-described configuration.
In the assembly procedure of No. 0, first, one ends of two Z guide shafts 124 are press-fitted into a Z-axis mounting portion 133 provided on the intermediate lens barrel 131, and one ends of two F guide shafts 144 are inserted into the intermediate lens barrel. It is press-fitted into the F-axis mounting portion 134 provided on the 131. Next, the connecting nut 123 is engaged with the Z moving frame 121. That is, the pipe portion 123a of the connection nut 123 is Z
Inserting into the groove 121d of the moving frame 121, the connecting nut 1
The 23 fitting portions 123b are fitted to the nut fitting portions 121f of the Z moving frame 121. At this time, the fitting portion 123b is elastically deformed in the direction of arrow a shown in FIG.
f and is sandwiched on the line A shown in FIG.
Therefore, even if an impact due to a drop or the like is applied to the camera lens barrel 100, the impact stress is applied on the line B shown in FIG. 6, so that the impact resistance can be improved.

The other end of one Z guide shaft 124 is inserted and penetrated into the bearing portion 121e of the Z moving frame 121 and the pipe portion 123a of the connecting nut 123, and the other end is inserted into the U groove 121c of the Z moving frame 121. Z guide shaft 124
Is inserted and penetrated, and the Z moving frame 121 is
31 is housed inside the one end surface side. Then, the other end of each Z guide shaft 124 is press-fitted into a Z-axis mounting portion 113 provided on the front lens barrel 111, and the front lens barrel 111 and the intermediate lens barrel 13 are pressed.
1 is screwed with a tapping screw 112. Accordingly, the Z moving frame 121 can move in the optical axis I direction inside the one end surface side of the intermediate lens barrel 131 with each Z guide shaft 124 as a guide.

Similarly, the connecting nut 143 is connected to the F-movement frame 14.
1 and the F guide shaft 144
Is inserted and penetrated, and the F moving frame 141 is
31 is housed inside the other end side. Then, the other end of each F guide shaft 144 is press-fitted into an F-axis mounting portion 154 provided in the rear lens barrel 151, and the rear lens barrel 151 and the intermediate lens barrel 13 are inserted.
1 is screwed with a tapping screw 153. This allows the F guide shaft 144 to move in the optical axis I direction inside the other end surface side of the intermediate lens barrel 131 with each F guide shaft 144 as a guide.

Next, the stepping motor 122 is housed in the motor mounting portion 132a of the intermediate lens barrel 131, and the lead screw 122a of the stepping motor 122 is connected to the rack portion 123c of the connecting nut 123, the stopper portion 123d, and the clamp spring portion 123e. Fit into the groove formed between them. Then, the stepping motor 122 is screwed to the intermediate lens barrel 131 with the tapping screw 125. Accordingly, the lead screw 122a of the stepping motor 122 is connected to the clamp spring 123 of the connection nut 123.
e to engage with the rack 123c.

Similarly, the stepping motor 142 is also housed in the motor mounting portion 132b of the intermediate lens barrel 131, and is screwed to the intermediate lens barrel 131 with a tapping screw 145. Thus, the lead screw 142a of the stepping motor 142 also engages with the rack 143c of the connection nut 143. Then, the iris 160 is crossed with the optical axis I so that the iris mounting portion 132 of the
c and inserted into the intermediate barrel 13 with the tapping screw 161.
Screw it to 1.

The stepping motors 122 and 142 of the camera lens barrel 100 assembled as described above.
When a drive current is applied to the terminal portions 122b and 142b from a drive circuit (not shown), each stepping motor 12
2, 142 lead screws 122a, 122a rotate. This rotational motion is converted to linear motion by the rack portions 123c and 143c of the connection nuts 123 and 143, and Z
The moving frame 121 and the F moving frame 141 are transmitted. Therefore,
The Z moving frame 121 and the F moving frame 141 are
Inside the one end surface side and the other end surface side of the Z guide shaft 124
And moves in the optical axis I direction along the F guide shaft 144.

The fitting portions 123b and 143b having the above-described configuration are used.
And the nut fitting portions 121f and 141f are fitted by an elastic force, so that the fitting accuracy does not need to be high as in the related art. Accordingly, the fitting accuracy is, for example, ± 0.
Since it is only necessary to process to about 01 mm, the processing cost can be reduced.

[0027]

As described above, according to the present invention, the connecting means and the moving frame can be easily connected.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a camera lens barrel according to the present invention.

FIG. 2 is a sectional side view of the camera lens barrel of FIG. 1;

FIG. 3 is a partial cross-sectional side view of the camera lens barrel of FIG. 1;

FIG. 4 is an exploded perspective view showing details of a moving frame and a connection nut of the camera lens barrel in FIG. 1;

FIG. 5 is a perspective view showing details of a main part of the connection nut of FIG. 4;

FIG. 6 is a plan view of a main part of the connection nut of FIG. 5;

FIG. 7 is a perspective view showing an example of a moving frame of a conventional camera lens barrel.

[Explanation of symbols]

100: lens barrel for camera, 110: first group lens, 111: front barrel, 113, 133 ...
Z-axis mounting part, 120 ... second group lens, 121 ...
Z-axis moving frame, 122, 145 ... stepping motor, 123, 143 ... connecting nut, 123b ...
Fitting portion, 123ba: slit, 124: Z guide shaft, 130: third lens group, 131: intermediate lens barrel, 134, 154: F-axis mounting portion, 140:
4th group lens, 141 ... F moving frame, 144 ... F
Guide shaft, 151: rear lens barrel, 152: element mounting part, 160: iris

Claims (2)

[Claims] 1. A front barrel having a first group lens, a first moving frame having a second group lens, an intermediate barrel having a third group lens, a second moving frame having a fourth group lens, and an image pickup device A camera lens barrel provided with a rear barrel having: a connecting means for connecting the first and second moving frames and respective driving means for moving the first and second moving frames, respectively; And a connecting means having a fitting portion fitted to the first and second moving frames by an elastic force. 2. The method according to claim 1, wherein said fitting portion is formed integrally with said connecting means so as to form a convex portion having a slit, and fits into a concave portion provided in each of said first and second moving frames. Item 2. A camera lens barrel according to item 1.